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Finding the Fourth Proportional to 128.98, 193.75 and 111.69

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Solution

The fourth proportional to 128.98, 193.75 and 111.69 is: 167.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.98 : 193.75 = 111.69 : x
  2. Step 2: Convert to fraction form
    128.98/193.75 = 111.69/x
  3. Step 3: Cross multiply
    128.98x = 193.75 × 111.69
  4. Step 4: Simplify right side
    128.98x = 21,638.97
  5. Step 5: Solve for x
    x = 21,638.97/128.98
  6. Step 6: Final answer
    x = 167.78

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.